AUTOMATED CAR FOR DOOR ENTRY:

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AUTOMATED CAR FOR DOOR ENTRY

• Zhen Hao Chng
• Mavis Rodrigues
• TA Paul Rancuret

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Inspiration for our project
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What is our project about?

• Automatic avoidance of obstacles
• Automated navigation out of parking area
• Prototype for implementation in motor vehicles

4
Design implementation
Controller
Sensors Data
Wireless RF transmission
PIC
CMOS H-Bridge
Motor
Steering Servo
5
Controller Purpose

• To start the device at a distance
• To stop the device for safety purposes
• To transmit the direction of un-parking
• Forward
• Backward

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Controller Select ON/OFF

• One Switch and Transmitter for ON/OFF
• Considering
• Bit 1 VCC (5V)
• Bit 0 Gnd (0V)

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Controller Select Direction

• One Switch and Transmitter for DIRECTION
• Considering
• Bit 1 VCC (5V)
• Bit 0 Gnd (0V)

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Controller Components

• Voltage regulator Device uses 5V
• Wireless Transmission
• Two Transmitters Linx TXM-900-HP3
• One Receiver (on Car) Linx RXM-900-HP3
• For User-Friendliness
• Two Switches Easy to make choice (On/Off and
  direction)
• Two LED To indicate users choice

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ControllerTesting Accuracy of Wireless
Transmission
MAX 5.8 V
Transmitter
MIN -800 mV
MAX 5.25 V
Receiver
MIN -560 mV
2.6us
Distance 5 m Scale 5us/div Frequency
40Khz
10
Controller Setting the channel
903.37Hz
0
CS0
0
CS1
0
CS0
0
CS2
Transmitters
On/off
From PIC
CS1
907.87Hz
0
CS0
1
0
CS1
CS2
0
CS2
Receiver
Direction
CS0, CS1, CS2 Set the Transmission and Receiving
Channels
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Controller Setting the channel
Receiver
903.37Hz
0
CS0
0
CS1
0
CS0
0
CS2
Transmitters
On/off
0 (From PIC)
CS1
907.87Hz
0
CS0
0
CS2
1
CS1
0
CS2
Reads ON/OFF Transmission
Direction
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Controller Setting the channel
Receiver
903.37Hz
0
CS0
0
CS1
0
CS0
0
CS2
Transmitters
On/off
1 (From PIC)
CS1
907.87Hz
0
CS0
0
CS2
1
CS1
0
CS2
Reads DIRECTION Transmission
Direction
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Controller Testing Time to Change Channel using
PIC
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Controller Testing Time to Change Channel using
PIC
Channel
Receiver Output
1.07ms
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Controller Testing Time to Change Channel using
PIC
CS1 from PIC
Receiver Output
1.04ms
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UltraSonic Sensors
Devantech SRF05
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UltraSonic Sensors
Distance 628/58 10.82 cm
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Sensitivity analysistest accuracy of sensors
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Sensitivity analysis
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ERROR CORRECTION

• Percentage error greater than 10 within 5 cm
• Reduce error by shifting sensors inwards
• Instead of measuring 17cm as clearancedistance,
  we take 22cm as clearance distance

5cm
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Infrared sensors
Sharp GP2D120
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Infrared sensors
-
V from IR sensor
V out
V Ref 0.6V
LM339A
LM339
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H-Bridge Purpose

• To amplify PIC current
• Easier to move car forward/backward
• Simple to invert the voltage across motor

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H-Bridge Components

• Consists of two CMOS inverters

S Source D Drain G Gate
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H-Bridge Working

• Motor is between the two inverters

M
M-
Back
Front
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H-Bridge Working

• The PMOS and NMOS acts like switches

PMOS
NMOS
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H-Bridge Working

• The PMOS and NMOS acts like switches

PMOS
NMOS
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H-Bridge Working
PMOS Switch
NMOS Switch
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H-Bridge Working
5V
0V
PMOS Switch
NMOS Switch
Input 0V
Input 5V
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H-Bridge Working
5V
0V
PMOS
NMOS
Input 0V
Input 5V
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H-Bridge Working
5V
0V
PMOS
NMOS
5 V across the Motor gt Forward
Input 0V
Input 5V
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H-Bridge Working
0V
5V
PMOS
NMOS
Input 5V
Input 0V
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H-Bridge Working
0V
5V
PMOS
NMOS
-5 V across the Motor gt Backwards
Input 5V
Input 0V
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H-Bridge Working
0V
0V
PMOS
NMOS
Input 5V
Input 5V
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H-Bridge Working
0V
0V
PMOS
NMOS
0 V across the Motor gt Stop
Input 5V
Input 5V
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H-Bridge Working
5V
5V
PMOS
NMOS
Input 0V
Input 0V
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H-Bridge Working
5V
5V
PMOS
NMOS
SHORTCIRCUIT AVOID!
Input 0V
Input 0V
Sure at least one input is 5 V
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H-Bridge Graph of Input/Output to CMOS
Front input
Front output
Back input
Back output
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H-Bridge Graph of Inputs to Motor
STOP
Front Motor input
Back Motor input
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H-Bridge Graph of Inputs to Motor
Forward
Front Motor input
Back Motor input
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H-Bridge Graph of Inputs to Motor
Backward
Front Motor input
Back Motor input
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Steering Servo

• Actuates the steering of the front wheels
• Fast actuators enable quick steering
• Consistent and easy to control

Futaba S3003
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Steering servo
Frequency 50Hz
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Steering algorithm
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Steering algorithm
Distance reading of sensors From PIC
All Distance readings gt Clear distance
NO
One Distance readings lt Too Near
YES
NO
SUCCESS!
YES
Steer Straight
Obstacle Avoidance
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Obstacle avoidance algorithmLeft Right
Steer Straight
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Obstacle avoidance algorithmleft lt Right
Turns 5
Turns 10
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Obstacle avoidance algorithmrightltleft
Turns 5
Turns 10
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Motor Testing the Power Requirement
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Motor Testing the Power Requirement
Using CMOS
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Motor Speed

• When all sensors are not clear, Voltage across
  the motor is 5V for 250ms
• Distance 3cm
• When all sensors are clear, Voltage across the
  motor is 5V for 500ms
• Distance 6cm
• Speed 12cm/sec

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Logical algorithm
Check RF Transmitter
System Off
ON
Pulse Sensors for Data
Compare Readings and RF Command
OFF
Different
Same
Steering Algorithm
Motor Steering Control
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Voltage regulator
LM78M05CT
12V
12V
12Vdc
12Vdc
LM78
LM78
LM78
5Vdc
5Vdc
5Vdc
CMOS
CMOS
Logic Circuit
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microcontroller
PIC16F877A

• Main brain for the system
• Reads signal from RF transmitter and enable
  state transition
• Pulse Ultrasonic Sensors and reads and evaluate
  data received
• Process algorithm for obstacle avoidance
• Outputs Logic to control CMOS to control Motor
• Process closed-loop state transition without
  user interaction

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Microcontroller
US_RX6
US_RX5
US_RX4
US_RX3
US_RX2
US_RX1
RECEIVER INPUT
CHANNEL SELECT
LED SIGNAL
STEERING
US_TX3
US_TX6
MOTOR -
US_TX5
MOTOR
US_TX4
US_TX2
LCD SERIAL
US_TX1
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LCD DISPLAY
BPI 216

• Easy to program and use
• Bright and Clear LCD
• Used for printing sensor readings
• Used for printing state of system and error
  debugging

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Success

• Wireless Transmission
• Receiving data from sensors
• Control the Receiver using PIC
• PIC integration with sensors
• PIC integration with steering
• Current Amplification
• Running the Motor

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Challenges

• PIC programming
• Powering the Motor
• Figuring out steering control
• Current amplification
• Understanding the Transmitter
• and receiver

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The next steps

• Improve algorithm to accommodate more test cases
• Use one transmitter by using a PWM
• Add more sensors to enable more robust algorithm
  and error checking detection
• Implement it on a real vehicle by scaling the
  range appropriately

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Questions?